The present invention relates to apparatus for manipulating substantially block-shaped commodities, such as cigarette packs or packs containing other smokers' products. More particularly, the invention relates to improvements in apparatus for filling gaps which develop at times in a continuous file or stream of commodities (hereinafter referred to as cigarette packs or packs) which are transported between a supplying machine and a processing or consuming machine.
Cigarette packs which are formed in a packing machine (e.g., in a machine of the type known as COMPASS produced by Hauni-Werke Korber & Co. KG., Hamburg, Federal Republic Germany) are transported to one or more further processing machines, for example, to a machine which applies revenue labels across the narrow front side faces of successive packs. As a rule, cigarette packs which issue from the packing machine form a single file of equally spaced or abutting packs which move lengthwise or sideways on toward the labelling station. For example, such single file or stream of cigarette packs can be transported by the horizontal upper reaches of two parallel belts defining a straight path along which the packs move sideways toward the labelling machine. In many instances, the file of packs exhibits gaps which develop as a result of removal of certain packs, e.g., because defective packs are expelled from the file before or immediately after they reach the aforementioned conveyor. The resulting gaps must be filled by admission of spare packs because many processing machines can operate properly only if they receive an uninterrupted stream or file of contiguous or equally spaced cigarette packs. Thus, many labelling machines will operate properly only if a row consisting of a predetermined number of packs is piled up immediately upstream of the labelling station.
The situation is analogous when a file of cigarette packs is fed to a carton filling machine which accumulates the oncoming packs into stacks and introduces one or more stacks into discrete containers, e.g., cartons consisting of cardboard or the like. The presence of a gap in the file of cigarette packs approaching the carton filling machine can result in accumulation of stacks containing less than the necessary number of packs so that the corresponding cartons must be ejected and their contents removed prior to reintroduction into the carton filling machine.
Gaps in a file of cigarette packs are also likely to develop at stations where successive packs of a series are transferred from a preceding conveyor onto the next-following conveyor. Therefore, the path along which the file of packs advances is monitored by photocells, mechanical sensors or other suitable detectors which transmit signals on detection of a gap, and such signals are used to effect the introduction of a spare pack into each gap ahead of the next-following (processing or consuming) machine.
U.S. Pat. No. 3,040,862 discloses an apparatus wherein a magazine for spare packs is adjacent to the conveyor for a single file of cigarette packs. A slide is employed to push a spare pack from the magazine onto the conveyor so that the spare pack expels a defective pack. The slide is movable at right angles to the direction of movement of the file of packs. In another embodiment, a defective pack is left on a platform and is expelled from the platform by the next-following satisfactory pack.
U.S. Pat. No. 3,342,350 discloses an intermittently operated conveyor for stepwise transport of packs from a supplying station, past several intermediate stations, and on to a receiving station. Vertical magazines above the intermediate stations serve for temporary storage of surplus packs or for delivery of packs to the conveyor. The packs which enter the supplying station are delivered to the conveyor by a first reciprocating pusher, and the packs leaving the receiving station are removed from the conveyor by a second reciprocating pusher.
A drawback which is common to both patented apparatus is that the pushers must perform relatively long strokes. The same applies for the transfer of packs from the magazine or magazines onto the conveyor or vice versa. Therefore, the output of such apparatus is relatively low. Furthermore, the patented apparatus are quite complex and expensive. The stations where spare packs enter the conveyor constitute bottlenecks and, therefore, such apparatus are not suited for transport of continuous files or streams of packs between a high-speed producing machine and a consuming machine whose output is sufficiently high to enable the consuming machine to accept all packs which issue from a modern packer or the like. In fact, the speed of modern cigarette packing machines and of machines which process packs issuing from packing machines is on the increase so that there exists an urgent need for apparatus which can adequately link such machines and insure the transport of a continuous file of equally spaced or contiguous packs.